This invention relates generally to printers, and more specifically to printing devices and techniques for monochrome and color printers capable of achieving high quality resolution.
High quality printers are typically characterized by numbers indicating their resolution in dots per inch (dpi). This resolution is usually described in the context of a two dimension coordinate system where one number indicates the resolution in the x-axis (as used herein, x-axis means the carriage scan axis for a swath printer), and another number indicates the resolution in the y-axis (as used herein, y-axis means the media advance axis for a swath printer). Thus, a resolution of 300/300 dpi generally indicates a carriage-scan axis resolution of 300 dots per inch and a media-advance axis resolution of 300 dots per inch.
The resolution of a printhead is primarily determined by the actual printout dot size as it appears in a printout. So in the ideal theoretical world, a 300 dpi printhead is presumed to produce a printout dot size which is approximately 1/300th inch in diameter. But various common language usages have developed which define resolution in other closely related terms. For example, a printhead's resolution is often identified by its nozzle pitch (i.e., the distance between adjacent nozzles on a printhead), and a print mode resolution is often identified by its pixel addressability (i.e., the distance between adjacent pixels in a printout).
There are several print mode techniques for expanding the print quality characteristics of a printhead. For example, a 1/300th inch nozzle pitch printhead could be used to create a 600 pixel/inch printout in the media-advance axis by changing the incremental advance distance of the media at the end of a swath and then employing a multi-pass print mode. As another example, a 1/300th inch nozzle pitch printhead could be used to create a 600 pixel/inch printout in the carriage scan axis by increasing the firing frequency of the printhead and/or changing the carriage scan speed.
However, implementing these different print modes is rather complicated and requires sophisticated programming techniques, precisely engineered mechanical parts, and many circuit components. Moreover, the print quality of a lower resolution machine which has a 300 dpi addressable print mode is not as good as the print quality of a true 600 dpi resolution machine where both smallest dot size and addressability are each equal to 600 dpi.